Cement for cans

[Scota4570]

What kind of cement is best for filling soda cans to be fired out of a mortar? Are there hints to getting the cans filled with cement in an efficient and neat way? Should I get some cement and sand and make my own mix? Obvioulsy agriggate is not going in the can easily.

An update, My tube is functionally done. It is about 5 1/2" OD. 9" of bore and about 15" total. 70-pounds? An empty pop can takes about 10 seconds to slide in due to air pressure. I'd say about 0.010" clearance. The bore came out great. I used a large boring bar and a high speed bit. It took only a few minuets of sanding to get an extremely smooth finish. The material seems to be some kind of alloy, maybe 4140? It was much tougher than the breech plug which was known to be mild steel. It has taken me about 15-hours to do the machining thus far. One pass with the boring bar took about 40 minuets. I had no idea how long big stuff takes, this has been an education for me. I'll post some photos when the trunion is on and the base is made.

 

[TheDoubleD]

You bore is to tight to shoot cans. You will have to do major cleaning after every shot to reload. Fouling won't let you load a second round.

The rule of thumb for proper windage is 1/40th. Divide the diameter of the can by 39 and multiply that by 40 and that will give you the correct bore diameter. Pop can is 2.6 inches so you bore should be 2.667

I just used that sakcrete stuff you can buy at the hard ware store. Be sure you get the spillage off the out side of the can or it will scour the bore.

What's the diameter of your powder chamber? The rule for loads in a mortar is that the diameter of the powder chamber is considered the bore for figuring loads. If the bore (powder chamber) is greater than 2 inches the guidline is 2 ozs. Cannon grade or Fg per inch is a max load.

Under 2 inch, I can look the load up.

For a starting load you want to start with a least 1/2 max load and may be even less. You are going to be very surpised how little powder it takes to make the can go a long ways. Much further than you expected.

Besides it's much more fun to see the can fly than to have a big blast and a large cloud of smoke and you have no Idea where the can went, then you see the Sheriff and the ambulance headed to the neighbors place.

By the way, a long time ago when I didn't know the powder chamber was the bore and the bore wasn't...I computed a max load for the can size and loaded with 2Fg and a solid lead 4 lb slug I made for a mould I built. I got the largest smoke ring i have ever seen, and the slug dissappeared with a crack. The results was my carraige was broken in half.

 

[Scota4570]

What's the diameter of your powder chamber?

One inch by about two inches deep.

 

[TheDoubleD]

Max load for a 1 inch diameter powder chamber is 185 grs Fg or Cannon grade.

 

[coehornboy]

I have used both aggregate and mortar mix without any stones. The aggregate is cheaper but makes inconsistant loads, as the weight greatly varies per can, and because there may be more aggregate in some than others, the cans can split when they land.

You should also make your loads up at least a week or two prior to shooting, as moisture makes the concrete brittle (I have had many damp rounds cause the cans to split upon impact).

There is no neat way to fill them. I cut the top of the soda can open the best I can with a can opener, and I make a funnel out of an old soda or water bottle. I don't worry too much about concrete on the outside as I scrub the dried concete off with a char-boy pad or another type of heavy-duty scrubberl. It comes off the aluminum pretty easily.

I also like to make coat hanger wire loops and anchor them deeply in the concrete. This has allowed me to carefully remove a round when needed, and if you attach a wire lead to it, you can attach long streamers to mark the trajectory of your shots.

Lastly, for accuracy, weigh your rounds, mark them with a sharpie, and group similar weight rounds together. This way you can hope for some consistancy, and you can alter your powder depending on the weight of the load. :v

 

[GunneyG]

What kind of cement is best for filling soda cans to be fired out of a mortar?

In my experience, the fiber reinforced concrete is best. Ordinary pre-mix is minimally strong for this application. I am using a Home Despot brand marked 5000 now and it seems OK.

 

[Will Bison]

I agree with Coehornboy, cut the tops off and use mortar mix, the stuff you use for setting brick or concrete block.

You will have to allow a proper drying period because the water can only get out through the top of the can.

The other option is soda cans filled with dry sand from Home Depot or Lowes. These are one shot deals but cheap and simple.

Bill